1. Field of the Invention
The present invention relates to a focal-plane shutter for an image-pickup apparatus.
2. Description of the Related Art
It is known that a slit formed by two pairs of shutter blade groups (leading blade and a trailing blade) continuously exposes an image-pickup surface as a focal-plane shutter for an image-pickup apparatus.
Each shutter blade group is formed by a plurality of arms, blades and pivoting members and reciprocates between a position covering an opening part of a shutter base plate and a position evacuating from the opening part of the shutter base. Additionally, the two pairs of shutter blade group are positioned in a blade room formed by three base plates including the shutter base plate.
Additionally, the shutter blade is controlled by an electric magnet when the shutter blade is operated by a driving member. The driving member bounds at the time of shutdown even if a stopper contacts the driving member since the focal-plane shutter having this configuration is operated at high speed when taking pictures. Additionally, if the stopper contacts the shutter blade, the blade may break. Thus, contraptions such as the driving blade abuts against a braking member urged by a spring (Japanese Patent Laid-Open No. 8-110546) is performed so as to prevent the situation.
However, since the braking member is position between at the blade driving member and the shutter blade plate in Japanese Patent Laid-Open No. 8-110546, an attracting portion such as an electric magnet and an armature is especially susceptible by particles generated at the braking member.